Stuart Kauffman, founder of the Sante Fe Institute, published this book in October 2000. Scientific American called his work "deep and challenging." Amazon has 26 sample pages for browsing; take a look.

From the Amazon review: "How can you tell when a scientific theory is revolutionary? As a rule, when a distinguished scientist says he's come up with a fourth law of thermodynamics, he's wrong. Stuart Kauffman may be the exception. ..."

One of Kauffman's key concepts is that of the adjacent possible ... the set of things that are only one step away from actual existence ... a metaphysical idea with real utility.

In this book, Kauffman applies complexity theory to fundamental questions about the origin and nature of life, not just on Earth but in general. But this book is not glossy pop-science; in places the arguments become quite technical and assume the reader already knows the background, vocabulary, etc. (or knows where to find it). To sum it up in a word, though: engaging.